standing: See Revelation 5:6; study note on Revelation 12:18.
144,000: God’s righteous remnant (see study note on Revelation 7:4–8).
The mark on their foreheads (contrast Revelation 13:16–17) is the name of both the lamb and his father, showing the unity of Jesus and the Father (see John 5:20–23; 14:5–10; 17:22).